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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/at_exit.h"
      6 
      7 #include <stddef.h>
      8 #include <ostream>
      9 
     10 #include "base/logging.h"
     11 
     12 namespace base {
     13 
     14 // Keep a stack of registered AtExitManagers.  We always operate on the most
     15 // recent, and we should never have more than one outside of testing, when we
     16 // use the shadow version of the constructor.  We don't protect this for
     17 // thread-safe access, since it will only be modified in testing.
     18 static AtExitManager* g_top_manager = NULL;
     19 
     20 AtExitManager::AtExitManager() : next_manager_(NULL) {
     21   DCHECK(!g_top_manager);
     22   g_top_manager = this;
     23 }
     24 
     25 AtExitManager::~AtExitManager() {
     26   if (!g_top_manager) {
     27     NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
     28     return;
     29   }
     30   DCHECK(g_top_manager == this);
     31 
     32   ProcessCallbacksNow();
     33   g_top_manager = next_manager_;
     34 }
     35 
     36 // static
     37 void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
     38   if (!g_top_manager) {
     39     NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
     40     return;
     41   }
     42 
     43   DCHECK(func);
     44 
     45   AutoLock lock(g_top_manager->lock_);
     46   g_top_manager->stack_.push(CallbackAndParam(func, param));
     47 }
     48 
     49 // static
     50 void AtExitManager::ProcessCallbacksNow() {
     51   if (!g_top_manager) {
     52     NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
     53     return;
     54   }
     55 
     56   AutoLock lock(g_top_manager->lock_);
     57 
     58   while (!g_top_manager->stack_.empty()) {
     59     CallbackAndParam callback_and_param = g_top_manager->stack_.top();
     60     g_top_manager->stack_.pop();
     61 
     62     callback_and_param.func_(callback_and_param.param_);
     63   }
     64 }
     65 
     66 AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
     67   DCHECK(shadow || !g_top_manager);
     68   g_top_manager = this;
     69 }
     70 
     71 }  // namespace base
     72